The successor to Microsoft Live OneCare, Security Essentials (full review here) takes a different approach to securing your computer. The program is free with core security features intact, but abandons the additional heft of a firewall, performance tuning, and backup and restore options. Under a clean and uncluttered interface, Security Essentials wraps antivirus and antispyware engines, rootkit protection, and real-time detection courtesy of Microsoft SpyNet, the unfortunately named cloud-based service that compares file behavior across computers.
There are four tabs, each with a concise, understandable label: Home, Update, History, and Settings. From Home you can run a Quick Scan, Full Scan, or Custom Scan, and a link at the bottom of the pane lets you change the scheduled scan. In the Settings window you can schedule scans, toggle default actions, adjust real-time protection settings, and create whitelists. An Advanced option here is still fairly basic, allowing you to set Security Essentials to scan archives, removable drives, create a system restore point, or allow all users to view the History tab. Security Essentials uses labels imported from OneCare: green for all good, yellow for warning, and red for an at-risk situation.
Independent test numbers for Security Essentials weren't available at the time of writing, although OneCare scored high detection rates. On a real-world machine, the Quick Scan completed in less than 30 seconds. Benchmarking tests from CNET Labs reveal that Security Essentials actually makes starting up and shutting down faster, but the Full Scan is much slower than many competitors. RAM usage was not insignificant, with 85 to 90MB used during a full scan, but it felt lighter. Security Essentials is basically a good set-it-and-forget-it security program, but if you want more options, you should look elsewhere.